Epoxy resins have found a wide range of uses in many industries since their commercial introduction. Industries in which epoxy resins are utilized as adhesives and coatings include the construction and electronics industries. Cured epoxy resins are noted for their low shrinkage, lasting adhesion, high dielectric strength, and chemical resistance. A major limitation of epoxy resins, particularly those intended for high temperature applications, is their inherent brittleness arising from their crosslinked structure. It is documented that development of approaches to toughening epoxy resins without sacrificing modulus and lowering the glass transition temperature (T.sub.g) would lead to an expansion of their use in areas such as primary aircraft structures, molding compounds and electrical and electronic components.
Methods for increasing toughness of epoxy adhesives are desired. In applications in the electronics industry, however, compositions that also maintain good thermal stability and adhesion to a wide variety of substrates are desirable.